The present invention relates generally to implants for the body and particularly to implants that have features that minimize or prevent rotation of an implant in a body. More specifically, the present invention is a breast implant that has an anatomical shape that gives a more natural look to the augmented breast, but cannot rotate because it has a texturing on the back that anchors it, yet is smooth on the surface to minimize rippling.
The preferred shape for an implant used for cosmetic breast augmentation is the so-called xe2x80x9canatomical shapexe2x80x9d that is also referred to as xe2x80x9ctear drop.xe2x80x9d This shape has more of the substance filling the silicone elastomer shell in the inferior pole of the implant and less in the superior pole, thus mimicking the natural shape of the breast. For a given volume, round shaped implants have too much substance in the upper pole that can make the breast look artificial. The anatomical implant looks much more natural.
A problem with anatomical implants is that if the outer surface of the implant is smooth, the implant can rotate. When an implant is surgically placed beneath the breast or beneath the chest muscle, the body recognizes that it is a foreign object and walls it off with tissue that is referred to as a xe2x80x9ccapsule.xe2x80x9d A smooth-walled implant creates a smooth capsule that can allow the implant to slip and slide within it. When a smooth-walled anatomical-shaped breast implant rotates, as it often does, there is more fullness laterally or medially instead of inferiorally as intended. This creates an unacceptable deformity. Thus far the only solution to this problem has been the use of xe2x80x9ctexturedxe2x80x9d implants which have a rough surface. They produce a capsule that is reciprocally rough. The xe2x80x9cmale-femalexe2x80x9d relationship of the implant and capsule holds the implant in place and prevents its rotation.
Textured implants have a very distinct disadvantage, however. The problem is that textured implants have a tendency to ripple (i.e. produce a folding, wrinkling or waviness on the surface of the implant). Rippling creates an extremely unsatisfactory appearance. Causes of or factors contributing to rippling may be 1) that textured implants are cured twice, while smooth walled implants are cured once, 2) that the textured implant is formed with an additional coating of the silicone elastomer, leading to a thicker wall that is less able to support itself and thus may fold, and/or 3) the texture itself (peaks and valleys in the surface of the implant) may produce a variety of non-linear scores or fold lines along which the wall of the implant folds or ripples.
Ripplingxe2x80x94visible or palpable waviness on the implant surfacexe2x80x94is one of the major problems with breast implants. This folding of the implant can often be felt or seen and can be extremely obtrusive. Therefore, to solve the problem of implant rotation with texturing the entire implant as is presently done, one must compound the problem of severe, unacceptable rippling.
The present invention provides a solution to the problem. The present invention is an implant that is textured on its posterior surface, but smooth on its anterior surface. The textured posterior surface causes a reciprocal textured capsule, but only behind the implant. This interlocking with the capsule keeps the implant from rotating. However, the textured area is only on the back of the implant; therefore, any rippling will not be visible or palpable. The anterior surface will remain smoothxe2x80x94and minimize any unsatisfactory rippling.
Preferred fill materials for the non-rotating anatomical-shaped breast implant include saline and viscous fill materials. Among viscous fill materials, silicone gel, soy oil, and hydrogels are preferred, with hydrogels being most preferred.
A feature of the present invention is a non-rotating breast implant.
Another feature of the present invention is a non-rotating anatomical-shaped breast implant.
Another feature of the present invention is an implant having a first surface portion that engages tissue in the body to anchor with little or no rotation the implant in the body and a second surface portion that has a desirable characteristic when oriented in a particular direction.
Another feature of the present invention is an implant having a textured surface portion that engages tissue growth in the body so as to anchor with little or no rotation the implant in the body and a second surface portion that is smooth.
Another feature of the present invention is a non-rotating anatomical-shaped breast implant with a posterior surface and an anterior surface where the posterior surface comprises a texture to anchor the implant in the body and where the anterior surface comprises a smooth face to minimize wrinkling.
Another feature of the present invention is a non-rotating breast implant having a first side with a relatively rough surface or surface portion to interlock with body tissue to anchor the implant and having a second side with a relatively smooth surface or surface portion that forms little or no wrinkles and that therefore may be oriented close to the skin to provide a natural appearance.
Another feature of the present invention is a method for minimizing or preventing rotation of an implant in a body so as to permanently fix the orientation of a desirable characteristic of the implant.
Another feature of the present invention is a method for minimizing or preventing rotation in a body of an anatomical-shaped implant so as to permanently fix the anterior orientation of the front side of the anatomical-shaped implant.
Another feature of the present invention is a method of making an envelope for an implant, where the method includes the separate steps of 1) fully submerging and 2) partially submerging a mandrel in a dispersion. The steps may occur in any sequence and be repeated.
The method includes selecting, preferably, an anatomical-shaped mandrel. Then the mandrel is dipped four times in a dispersion of a silicone elastomer and solvent (such as xylene). After each of the dips, the solvent is permitted to evaporate or partially evaporate so as to permit the just-coated layer to at least partially stabilize. After the fourth layer of silicone elastomer (or other envelope forming material) has stabilized, the envelope (still on the mandrel) is cured. The cured envelope, still on the mandrel, is then partially dipped into the dispersion, i.e., partially submerged to the level or over the portion of the envelope to which the texturing is to be applied. This layer (over a portion of the envelope) is then permitted to stabilize (but is not fully dried). Then granulated solid particles, such as salt particles (sodium chloride for example), are applied over (such as by being sprayed) the portion of the envelope that has the extra layer of now stabilized but not fully dried silicone elastomer. This portion of the envelope is the portion that is not perceptible (visibly or by touch) when the implant is implanted into the body. Preferably, such portion of the implant is the posterior side of the implant. Then the envelope is cured (vulcanized). After being cured, the envelope (still on the mandrel) is soaked in a solvent (such as water) to dissolve or wash off the solid granules, thereby leaving the textured surface. The envelope is then removed from the mandrel, patched and fitted with a valve for the fill material.
Another feature of the present invention is a breast implant having a first thickness at the nipple position and a second thickness on the posterior side.
An advantage of the present invention is that anatomical-shaped breast implants are held in position, with their superior poles correctly oriented in the superior position without slippage or spin off in the medial or lateral directions.
Another advantage of the present invention is that the anterior side of the breast implant takes on a more natural appearance and feel. Since the implant is anchored in place by tissue engaging the textured posterior side of the implant, the anterior side of the implant need not be textured and therefore may be made of a thinner envelope wall having a smooth surface. Thinner, smooth, once-cured envelope walls have less of a tendency to wrinkle or ripple than do thicker, textured, twice-cured walls. A wrinkle or ripple may be seen and/or felt through the skin of the natural breast.